teo, u obviously didnt read my post. You would have seen it was addressed to comments byt "the child ..." and not you. I would help if you actually learned to (a) read; (b) assimilate; (c) understand ... before making rash comments.

@sidevalve
Step 1: Charge the battery to full the day before takeoff.
Step 2: Take off around noon to ensure maximum solar cell output.
This way, you get full battery power AND full solar power going into the motors for take-off.

I'm setting up one but it will be used only as a point of contact. There is a very large amount of preparation to be done before getting anywhere near to the public.
To give you an idea of what we do: Something similar to Better Place (the battery-swapping company) but on a different section of the market and with a slightly different business model.

And your link answer the question that was raised before: The plane will take off by itself.

I'm going off-topic, and I hope you'll forgive me for this.
I'm involved in a company's start-up that involve a project similar in its principle: Using current technologies in a bold and brand new way.

I've conduced a lot of research so far, and most of the time when I get involved with green communities online, I find the same kind of extreme thinking where people discuss in profound details how this proposed solution will pollute anyway. Most of the time they use this as a springboard to advertise a radical green agenda, which has often very little chances of working out as it is too extreme for most people.
They most often miss by far the actual vision and green potential of new projects, failing to understand that you need to start somewhere.
I see it as a new form of bigotry, and good old short-sightedness.
Is this conversation going the same way?

First of all you don't have to be insultive. We are just talking. Secondly, seing from your nickname and your reaction, you remain more of a baby than I am.

I'm telling you all this because everyday I go visit this project and I see those 60ish engeneers, some from the finest aircraft companies working day and night for this project and 300 consultant engeneers involved from the most famous aircraft makers. The project is supported by ESA. Don't you think those people "kind" of know what they are trying to achieve? I know their goals, that is why I dare to tell you.

It seems impossible for most of you(sidevalve); it shows that they are pushing the limits of our technologies you know about today.

Finally, yes it pollutes but it seems normal to me yet.Why? Are you asking to find solution for our futur without even polluting in the research? Again, you may not find this plane as a solution, but it can inspire a start. Even in this blog people are puuting some idea after reading the article ;)

@"The child ..."
Results from LCAs (lifecycle assessments) of solar PV cell production, to which i presume u refer, are hotly disputed. And in any case pollution during production depends a lot on the source of energy used to produce your solar cells.

Thus if you purchased your cells from China (which i doubt this flight's proponents did), then yes you might be looking at 10 - 15 years of worth of pollution at the rate of energy production expected from the cells. Remember though that solar cells have a life-span of about 25 years so even this remains "carbon positive", so to speak.

On the other hand if you purchased your cells from a German manufacturer, who uses solar THERMAL energy for electricity generation to power their plant, then you might be looking at 1 -2 years (due to the carbon produced in constructing the power plant).

I must strongly disagree with some of the commentary on this article. It seems to been based on a very linear thought process.

This flight identified one of the primary wastes involved in long distance flight and attempted to adress it in a small scale format.

The weight of the fuel itself causes the flight to consume more fuel. Therefore, the increase in fuel required for longer flights does not happen linearly. To reduce the weight of the fuel, the time it is carried or even part of the fuel is a savings in itself.

This is a valuable spring board for more research. Just as we did not jump directly from signal flags to iphones, this will likely take multiple steps and these steps will not always be in the same vector.

Certain technolgies may work better in different periods of the flight. This experiment is already employing multiple technologies in both direct solar power and battery back up. Why not one more or even a partial supplementation or exchange of another?

As to the question of lift off; why are you so certain the the power for this needs to be contained in the plane itself to avoid fossil fuels? This is one of the parts of the fuels that may be more efficient left on the ground instead of being lifted off with the craft. (not a brand new idea if you follow the development of the space program)

Solving climate change, the challenge of our generation, does not necessarily involve using spanking brand new technologies. It's also about combining current technologies in innovative ways that makes a difference. In fact, if history indicates anything, it is that this approach will quite likely make the biggest difference.

Through this project, Solar Impulse shows that it is possible to marry current technologies in an innovative way to achieve results of a different scale. It's not about how much CO2 this exact plane will produce or not, it's about the possibilities this novel way of devising things open.
None of us can actually forecast the consequences and potential application of this endeavor, so we should be careful not to criticize it in a short-sighted consideration.

PS: Solar-cells on regular jet planes to replace the Auxiliary Power Unit are simply not a practical idea in terms of industrial application.

Teo123 - I am not negative. I am a realist. There is no point in us deluding ourselves that technologies like this will 'save the world' if they turn out to be blind alleys. If this turns out to be one it will have diverted attention from other potentially more worthwhile technologies. And I think you have misunderstood my point - I am not talking about the aircraft's ability to remain in the air and rise and fall once it is up there (gliders can do that, so this would be no big technical advance. However, gliders do not carry passengers or cargo). I am talking about its ability to get off the ground into the air in the first place. With the power figures quoted this is impossible without external (power-consuming) help. Finally, we take ecology very seriously in the UK as well, but we have a considerably larger population whose needs we have to service, and a considerably lower standard of living and per capita income to achieve it from.

No no, it will be an independant plane... no towed by anything. During the day, the plane will have to charge the batteries, go up, and keep enough energy to pass the entire night on a slight down slope.

Maybe the production releases some harmful emissions, but it's at least an "investment" to green operation for years. If you think 2 seconds, anything you build costs some energy, electricity and so on. Nowdays we can't have the ambition of building means of transportation that are green (except maybe a skateboard)and does not consume any kind of energy for the production. Anyway we are going to consume and harm the planet but at least it will be for something durable and not ephemere.

Anyway, I'm from Switzerland where we take ecology very seriously and I'm very suprised by your negativity.

How will it get off the ground? With the power figures quoted it will only (just) be able to sustain itself in level flight, but there will be no way any solar powered plane will be able to take off under its own power. So presumably it will need to be towed by something else to get off the ground (like gliders do). And presumably that something else will use fossil fuels. So bang goes the zero emissions idea right from the start (literally)...

Yes, I'm sorry maybe I did not express my idea clearly enough. One hundred years ago, people did not see a direct line into the solution of building those big air planes but it demonstrated at least that flying was even possible and it inspired others to work on it!

What I was trying to say was that maybe through this specific airplane you do not see a solution for tomorrow's means of transportation (which is abselutly right, because we're not even close to find the solution), but if they can achieve this challenge it will demonstrate that we can push our technologies and hopefully achieve a green tour around our world. Who knows, they might inspire some other great leaders... Instead of putting 90 million in a Hollywood movie, I'm greatfull those people do something more innovative.

teo123, your comparison with the Wright brothers plane doesn't exactly back up your point, you say it was simply a significant start (which eventually led to large commercial planes) I think that is the reason why people are making the comparison

ntrgc89, you think putting solar cells on planes now would be a good idea to power things like cabin lighting. The reason they do not do this is because as you will know cabin lighting is used not only when it is light outside but also when it is dark. If this was to be demanded of the solar lighting idea very large batteries would be needed. Carrying these batteries would not only be inefficient but would also probably use more engine power than the engine initially powering the lighting anyway. A powerful jet engine produces thousands of kilowatts of power, it has no trouble providing power to a few kilowatts of lighting and electrics. The batteries would also be another hazard on a plane and I am pretty sure it would be extremely expensive to produce solar cells that are capable of withstanding the huge amount of flexing within a commercial aircraft wing.

It is my recollection that the Germans, sometime in the 1980's, first flew a manned [personed?] solar-powered aircraft designed pretty much the way described in your article. The motor was part of the tail structure.
This long distance model then would be a step further along the road!

I think you guys completely miss the point of the adventure. You are all directly thinking if we can use it tomorrow with 250 passenger, if we can make money out of it and so on. Did you think that the Wright brothers thought of building an airplane with 300 passengers crossing the atlantic in 1902 when they were struggling to fly for 30 sec? Abviously no, but it was a significant START.

We are nowadays completely dependant on fossil energies and we have a rediculous consumption rate that will either need to be changed or replaced. And for that guys, we need some people like the wright borthers to take the lead and START a hope and a mouvement that we can win this "impossible" (for today) bet... Thank you Solar Impulse.

Instead of doing nothing and just consuming, we can be greatfull to those people/leaders.